So, what might be the range for that?
High altitude VOR ranges are, what, in the 200 mile range?
That leaves 2600 miles to cover away from land on a 3000 mile trans-atlantic crossing.
Compare to using satellites, always overhead, any weather.
Sats are, of course, much better. I was just considering what could be done on a small budget.
Ham operators are capable of creating the simple system I described.